1. Field of the Invention
The present invention relates to pressure gauges of the type carried on a vessel being monitored. More particularly, the invention relates to a mechanical indicator of pneumatic pressure which indicates by color coding whether the pressure being monitored is within specifications. In alternative embodiments, the novel indicator cooperates with or is an integral part of a valve enabling the vessel to be filled with compressed gas.
2. Description of the Prior Art
Pneumatic tires are designed to operate at pressures within narrow predetermined ranges. Typically, tires lose pressure and must be reinflated to specified values by the operator. This maintenance operation requires a pressure gauge. Many operators rely upon service facilities offering compressed air to supply the gauge. If the service facility does not supply a gauge, the operator of the vehicle is obliged to furnish the gauge. It is easy to neglect to bring a tire pressure gauge at all times, and the operator may therefore lack a gauge when desiring to restore or check tire pressure. Even if a pressure gauge is at hand, it is not always convenient to utilize typical tire pressure gauges. Pressure gauges are normally designed to operate when pressed against the valve of the tire sufficiently to release pressure so that it may be measured and indicated. Under conditions of severe temperatures, dust, rain, and other influences, it may prove difficult or unpleasant to check tire pressure.
One answer to this problem is to furnish a pressure gauge that is left in place on the tire, the gauge having an indicator which may be readily viewed to ascertain tire pressure. Such gauges have been proposed in the prior art.
In an indicator shown in U.S. Pat. No. 5,569,849, issued to Craig Cummings on Oct. 29, 1996, a colored liquid flows around a solid member obstructing view of the colored liquid when tire pressure deviates from a predetermined setpoint. Visibility of the colored liquid indicates inadequate pressure. By contrast, in the present invention, a solid colored member aligns with a window formed in the indicator. In the novel indicator, air pressure from the tire acts directly on the solid member. No fluid apart from compressed air contained in the tire is employed.
U.S. Pat. No. 5,103,670, issued to Min-Yu Wu et al. on Apr. 14, 1992, shows an indicator having a bellows operated piston which, when appearing in a window formed in the indicator, aligns with indicia indicating pressure values. By contrast with this approach, the present invention exposes indicia, preferably in the form of a predetermined color, which enables immediate discernment of whether pressure is within specifications. There are no bellows in the present invention.
U.S. Pat. Nos. 5,503,012 and 5,606,123, issued to Masoud Rabizadeh respectively on Apr. 2, 1996, and Feb. 25, 1997, both are based on a ball visible through a window which aligns with indicia. Rabizadeh improves on prior art devices by providing a magnifying glass over the window. However, graduation indicia must still be read in order to determine pressure within the tire. In the present invention, mere discernment of color is required to obtain the same information. There is no magnifying glass required in the present invention.
The subject indicator shown in U.S. Pat. No. 5,641,902, issued to Jung Un Hong on Jun. 24, 1997, incorporates an inflatable member which displays indicia indicating inflation pressure. By contrast, in the present invention, a color signal is visible through a window to indicate tire pressure. There is no inflatable member in the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention enables a vehicle operator to determine sufficiency of tire pressure at a glance. There is no necessity of pressing an instrument against the valve. It is not even necessary that the indicator be fully visible and unobscured, since any glimpse of a predetermined color immediately conveys the sought information. Therefore, minor accumulation of dust and dirt, which are normally present under driving conditions, would usually not affect function of the invention.
The invention comprises a tubular housing or body which protrudes inwardly radially from a wheel, in the usual location of filling valves for pneumatic tires. It has a window revealing an indicating member which is color coded to indicate tire pressure relative to predetermined pressure values. The indicating member has colors signifying excessive pressure, proper pressure, and low pressure. The user will determine at the state of inflation of the tire at a glance.
The novel indicator may be fabricated to mount to conventional filling valves by a threaded attachment. Alternatively, it may be configured to supersede the usual filling valve. In either form, the novel indicator is carried on the tire being monitored for pneumatic pressure after installation, and need not be removed. The novel indicator is optionally configured to enable inflation in the usual manner without removing the indicator from the valve or tire.
Accordingly, it is a principal object of the invention to provide a tire pressure indicator that is carried on a tire being monitored.
It is another object of the invention that the novel indicator provide visual indication of whether the pressure is within specifications by color coding.
It is a further object of the invention to indicate high and low pressure conditions as well as proper inflation pressures.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.